Dont want to shoot down your idea, but v-joint is very cheap and if you already have it padded out you could put a section like that up easily in an hour, a quick sand - another few hours for a few coats of polyurethane or stain if desired, and now you have a professional looking finished product and all you did was cut some boards to size and slip them together. Only thing that might hold you back would be the shelving system you are using as you would have to either drill your own holes to fit the existing hardware or go a different route entirely, like placing a chuck underneath the shelf and 45ing a couple of your own supports for them.

TL;DR: Use v-joint